1. Field of Invention
The present invention relates to a motor power train, particularly to a power train for an electric motor of an electric vehicle or a four-wheel-drive electric vehicle in which the electric motor is used in combination with an internal combustion engine (a fuel engine), and to a method of assembling the same.
2. Description of Related Art
Japanese Patent Application Laid-Open No. 9 (1997)-226394 discloses a drive system for an electric vehicle, which is composed of an electric motor, a reducer and a differential.
However, in this drive system, a gear on an intermediate shaft and a large-diameter portion of the differential overlap in axial position. A gear fixed to a flange of a differential case with bolts and a differential gear unit also overlap in axial position. This arrangement requires a large distance between the intermediate shaft and the differential, resulting in a large overall size of the drive system with its degraded mountability.
Moreover, in order to assemble this drive system, a gear is set to an output shaft of the electric motor, and then a center distance between the output shaft and the intermediate shaft is adjusted for proper engagement of gears on both shafts. Such assembly is difficult and thereby costly.